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c# - 如何从实体框架数据库中获取包含在类中的项目列表

问题描述

我的申请有问题。我无法从数据库中获取其中包含列表的对象。我真的不擅长实体框架，如果这是一个很大的错误，我很抱歉。

public List<Recipe> GetRecipes(Cook cook)
    {
        List<Recipe> L_Recipes = new List<Recipe>();
        Cook Cook = dbc.DbCook.SingleOrDefault(c => c.Nickname == cook.Nickname);
        L_Recipes = Cook.ListRecipes;
        return L_Recipes;
    }

这是Recipe课程：

  public class Recipe
{
    //Attributes
    public int Id { get; set; }
    public string Name { get; set; }
    public string Type { get; set; }
    public float CostPrice { get; set; }
    public float SellingPrice { get; set; }
    public DateTime Date { get; set; }
    public List<Ingredient> ListIngredients { get; set; }
    public List<Comment> ListComments { get; set; }
    public Schedule Schedules { get; set; }
    //Builder
    public Recipe(string name, string type)
    {
        Name = name;
        Type = type;
        Date = DateTime.Now;
        ListIngredients = new List<Ingredient>();
        Schedules = new Schedule();
    }
    public Recipe(string name,string type,float costPrice,float SellingPrice,DateTime Date,List<Ingredient> ListIngredients,List<Comment> ListComments,Schedule Schedules)
    {
        this.Name = name;
        this.Type = type;
        this.CostPrice = costPrice;
        this.SellingPrice = SellingPrice;
        this.Date = Date;
        this.ListIngredients = ListIngredients;
        this.ListComments = ListComments;
        this.Schedules = Schedules;
    }
    public Recipe() { ListIngredients = new List<Ingredient>(); }
    //Methods
    public void AddIngredient(Ingredient i)
    {
        ListIngredients.Add(i);
    }
    public float CalculCostPrice()
    {
        float cost = 0;
        foreach (Ingredient ing in ListIngredients)
        {
            cost += ing.CalculCostIngredient();
        }
        return cost;
    }
    public float CalculSellingPrice()
    {
        return (float)(CalculCostPrice()*1.05);
    }
    public override string ToString()
    {
        string SP = string.Format("{0:00.00}", SellingPrice);
        return $"{Name} for {SP} euros added the {Date.ToString()}";
    }
}

问题是我收到了食谱的信息，但没有收到其中的清单。

它在 ASP.NET 中

包括代码：

        public List<Recipe> GetRecipes(Cook cook)
    {
        List<Recipe> L_Recipes = new List<Recipe>();
        Cook Cook = dbc.DbCook.Include(c => c.ListRecipes).singleOrDefault(c => c.Nickname == cook.Nickname);
        L_Recipes = Cook.ListRecipes;
        return L_Recipes;
    }

标签： c#.netasp.net-mvc

解决方案

感谢https://stackoverflow.com/users/395675/philip-smith和https://stackoverflow.com/users/5748194/felipe-deveza 所以答案是使用 Include 并添加 using include:public List<Recipe> GetRecipes(Cook cook) { List<Recipe> L_Recipes = new List<Recipe>(); Cook Cook = dbc.DbCook.Include(c => c.ListRecipes).singleOrDefault(c => c.Nickname == cook.Nickname); L_Recipes = Cook.ListRecipes; return L_Recipes; } 和 using：using System.Data.Entity;

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